WesWorld

Three minor ships :

First is a purpose built training cruiser.
Second is a potential subchaser.
Last is a Belgian sloop.

When the Dutch converted some old cruisers a couple years ago, it was with the expectation they would be followed by purpose-built vessels...which I nearly forgot.

The stop gap conversion of an old cruiser into a training vessel has been viewed as a success, but is very close to the end of it's service life.

Further, substantial new equipment is entering the fleet. A new purpose built cruiser has been designed to mount a variety of fleet weapons, the newest electronics, both diesel and steam plants, and a floatplane on the fantail.

Armor is restricted to weatherproof housings on the guns, and a splinterproof protected cruiser scheme.

Witte de Withe, Netherlands Training Cruiser laid down 1935

Displacement:
2,798 t light; 2,995 t standard; 3,551 t normal; 3,996 t full load

Dimensions: Length overall / water x beam x draught
393.70 ft / 393.70 ft x 42.65 ft x 15.75 ft (normal load)
120.00 m / 120.00 m x 13.00 m x 4.80 m

Armament:
6 - 5.98" / 152 mm guns (2x3 guns), 110.23lbs / 50.00kg shells, 1925 Model
Breech loading guns in turrets (on barbettes)
on centreline, all forward, 1 raised mount - superfiring
4 - 4.92" / 125 mm guns (2x2 guns), 59.52lbs / 27.00kg shells, 1926 Model
Dual purpose guns in deck mounts with hoists
on side, all aft
4 - 3.94" / 100 mm guns (2x2 guns), 30.51lbs / 13.84kg shells, 1928 Model
Dual purpose guns in deck mounts with hoists
on side, all forward
8 - 1.57" / 40.0 mm guns (2x4 guns), 1.95lbs / 0.88kg shells, 1933 Model
Anti-aircraft guns in deck mounts
on side, all amidships
8 - 0.91" / 23.0 mm guns (4x2 guns), 0.37lbs / 0.17kg shells, 1934 Model
Anti-aircraft guns in deck mounts
on side ends, evenly spread
Weight of broadside 1,040 lbs / 472 kg
Shells per gun, main battery: 200
8 - 18.0" / 457.2 mm above water torpedoes

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 0.79" / 20 mm 262.47 ft / 80.00 m 8.01 ft / 2.44 m
Ends: Unarmoured
Main Belt covers 103 % of normal length

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.39" / 10 mm 0.20" / 5 mm 0.20" / 5 mm
2nd: 0.39" / 10 mm 0.20" / 5 mm 0.20" / 5 mm
3rd: 0.39" / 10 mm 0.20" / 5 mm 0.20" / 5 mm
4th: 0.39" / 10 mm 0.83" / 21 mm -
5th: 0.39" / 10 mm - -

- Armour deck: 0.79" / 20 mm, Conning tower: 1.18" / 30 mm

Machinery:
Oil fired boilers, steam turbines plus diesel motors,
Electric motors, 2 shafts, 22,674 shp / 16,915 Kw = 26.00 kts
Range 8,500nm at 15.00 kts
Bunker at max displacement = 1,002 tons

Complement:
229 - 299

Cost:
£1.504 million / $6.015 million

Distribution of weights at normal displacement:
Armament: 128 tons, 3.6 %
Armour: 253 tons, 7.1 %
- Belts: 69 tons, 1.9 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 20 tons, 0.6 %
- Armour Deck: 159 tons, 4.5 %
- Conning Tower: 6 tons, 0.2 %
Machinery: 644 tons, 18.1 %
Hull, fittings & equipment: 1,373 tons, 38.7 %
Fuel, ammunition & stores: 753 tons, 21.2 %
Miscellaneous weights: 400 tons, 11.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
3,603 lbs / 1,634 Kg = 33.6 x 6.0 " / 152 mm shells or 0.9 torpedoes
Stability (Unstable if below 1.00): 1.03
Metacentric height 1.5 ft / 0.4 m
Roll period: 14.8 seconds
Steadiness - As gun platform (Average = 50 %): 72 %
- Recoil effect (Restricted arc if above 1.00): 0.94
Seaboat quality (Average = 1.00): 1.25

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.470
Length to Beam Ratio: 9.23 : 1
'Natural speed' for length: 19.84 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 21.82 ft / 6.65 m
- Forecastle (20 %): 17.85 ft / 5.44 m (13.88 ft / 4.23 m aft of break)
- Mid (50 %): 13.88 ft / 4.23 m
- Quarterdeck (15 %): 13.88 ft / 4.23 m
- Stern: 13.88 ft / 4.23 m
- Average freeboard: 14.99 ft / 4.57 m
Ship tends to be wet forward

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 100.3 %
- Above water (accommodation/working, high = better): 95.4 %
Waterplane Area: 10,893 Square feet or 1,012 Square metres
Displacement factor (Displacement / loading): 120 %
Structure weight / hull surface area: 74 lbs/sq ft or 359 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.83
- Longitudinal: 1.97
- Overall: 0.91
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily



Of the 400 tons misc. weight,
25- Catapult and floatplane
25- Torpedoes
100- reserved for current and future sensor sets.
250- classrooms, training rooms, additional accomodations.

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SC-1, Netherlands Subchaser laid down 1935

Displacement:
137 t light; 144 t standard; 149 t normal; 154 t full load

Dimensions: Length overall / water x beam x draught
98.43 ft / 98.43 ft x 19.69 ft x 5.58 ft (normal load)
30.00 m / 30.00 m x 6.00 m x 1.70 m

Armament:
1 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1935 Model
Anti-aircraft gun in deck mount
on centreline forward
4 - 1.57" / 40.0 mm guns (1x4 guns), 1.95lbs / 0.88kg shells, 1935 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
4 - 0.91" / 23.0 mm guns (2x2 guns), 0.37lbs / 0.17kg shells, 1935 Model
Anti-aircraft guns in deck mounts
on side, all amidships
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1935 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 22 lbs / 10 kg
Shells per gun, main battery: 200

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.39" / 10 mm - -
2nd: 0.31" / 8 mm - -
3rd: 0.31" / 8 mm - -
4th: 0.31" / 8 mm - -

- Conning tower: 0.39" / 10 mm

Machinery:
Oil fired boilers, complex reciprocating steam engines,
Direct drive, 1 shaft, 445 ihp / 332 Kw = 13.50 kts
Range 1,600nm at 8.00 kts
Bunker at max displacement = 10 tons

Complement:
20 - 27

Cost:
£0.054 million / $0.217 million

Distribution of weights at normal displacement:
Armament: 3 tons, 1.9 %
Armour: 1 tons, 0.7 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 1 tons, 0.5 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.2 %
Machinery: 25 tons, 16.7 %
Hull, fittings & equipment: 62 tons, 41.3 %
Fuel, ammunition & stores: 12 tons, 7.9 %
Miscellaneous weights: 47 tons, 31.5 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
173 lbs / 78 Kg = 13.4 x 3.0 " / 75 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 0.99
Metacentric height 0.4 ft / 0.1 m
Roll period: 12.7 seconds
Steadiness - As gun platform (Average = 50 %): 66 %
- Recoil effect (Restricted arc if above 1.00): 0.15
Seaboat quality (Average = 1.00): 1.33

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.483
Length to Beam Ratio: 5.00 : 1
'Natural speed' for length: 9.92 kts
Power going to wave formation at top speed: 64 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 10.93 ft / 3.33 m
- Forecastle (20 %): 8.92 ft / 2.72 m (6.96 ft / 2.12 m aft of break)
- Mid (50 %): 6.96 ft / 2.12 m
- Quarterdeck (15 %): 6.96 ft / 2.12 m
- Stern: 6.96 ft / 2.12 m
- Average freeboard: 7.51 ft / 2.29 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 104.1 %
- Above water (accommodation/working, high = better): 80.7 %
Waterplane Area: 1,218 Square feet or 113 Square metres
Displacement factor (Displacement / loading): 124 %
Structure weight / hull surface area: 29 lbs/sq ft or 141 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.99
- Longitudinal: 7.13
- Overall: 1.20
Caution: Poor stability - excessive risk of capsizing
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is cramped
Good seaboat, rides out heavy weather easily

An attempt at a more worthy coastal protection vessel.
Equipped with hydrophones (10t) and depthcharges or mines (32t) there is little excess room (5t).

The ship is overbuilt, and not overly fast, but is perfectly capable of bird-dogging a submarine.
The 30m design means 2 should be buildable in a 70m slip, with 10m between.


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Last is a Belgian sloop. Meant for fisheries protection and with a secondary training role.

Artvelde, Belgium Sloop laid down 1935

Displacement:
1,124 t light; 1,154 t standard; 1,274 t normal; 1,369 t full load

Dimensions: Length overall / water x beam x draught
331.22 ft / 321.52 ft x 45.93 ft x 6.56 ft (normal load)
100.96 m / 98.00 m x 14.00 m x 2.00 m

Armament:
1 - 4.13" / 105 mm guns in single mounts, 35.32lbs / 16.02kg shells, 1935 Model
Quick firing gun in a deck mount with hoist
on centreline forward
4 - 1.46" / 37.0 mm guns (2x2 guns), 1.55lbs / 0.70kg shells, 1934 Model
Anti-aircraft guns in deck mounts
on side, all amidships
8 - 0.52" / 13.2 mm guns (4x2 guns), 0.07lbs / 0.03kg shells, 1928 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 42 lbs / 19 kg
Shells per gun, main battery: 200

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.31" / 8 mm 0.31" / 8 mm -
2nd: 0.31" / 8 mm - -
3rd: 0.31" / 8 mm - -

Machinery:
Coal fired boilers, steam turbines,
Geared drive, 2 shafts, 3,351 shp / 2,500 Kw = 18.00 kts
Range 5,500nm at 10.00 kts
Bunker at max displacement = 214 tons (100% coal)

Complement:
106 - 138

Cost:
£0.297 million / $1.189 million

Distribution of weights at normal displacement:
Armament: 5 tons, 0.4 %
Armour: 1 tons, 0.1 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 1 tons, 0.1 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.0 %
Machinery: 105 tons, 8.2 %
Hull, fittings & equipment: 842 tons, 66.1 %
Fuel, ammunition & stores: 150 tons, 11.8 %
Miscellaneous weights: 170 tons, 13.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
6,299 lbs / 2,857 Kg = 178.3 x 4.1 " / 105 mm shells or 2.4 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 1.9 ft / 0.6 m
Roll period: 13.9 seconds
Steadiness - As gun platform (Average = 50 %): 83 %
- Recoil effect (Restricted arc if above 1.00): 0.04
Seaboat quality (Average = 1.00): 1.66

Hull form characteristics:
Hull has rise forward of midbreak
Block coefficient: 0.460
Length to Beam Ratio: 7.00 : 1
'Natural speed' for length: 17.93 kts
Power going to wave formation at top speed: 40 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 19.75 ft / 6.02 m
- Forecastle (20 %): 19.75 ft / 6.02 m
- Mid (50 %): 19.72 ft / 6.01 m (11.71 ft / 3.57 m aft of break)
- Quarterdeck (15 %): 11.71 ft / 3.57 m
- Stern: 11.71 ft / 3.57 m
- Average freeboard: 15.73 ft / 4.79 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 45.8 %
- Above water (accommodation/working, high = better): 263.1 %
Waterplane Area: 9,499 Square feet or 882 Square metres
Displacement factor (Displacement / loading): 301 %
Structure weight / hull surface area: 62 lbs/sq ft or 304 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.10
- Longitudinal: 2.79
- Overall: 1.21
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Excellent seaboat, comfortable, can fire her guns in the heaviest weather

Designed primarily as a North Sea fisheries protection vessel, but also as coastal patrol.

Fitted with hydrophones and 4 DC throwers on the fantail (50t), as well as extra accommodations to allow some use as a training ship (100t), and some design slack for future growth (comp hull & 50t).

The 105mm and 37mm are by FRC (Fonderie Royale de Cannons), while the FN 13.2mm is the same as developed by Browning for the Netherlands.

On the training cruiser:

Nice. If you wanted to use a version of this ship as an escort cruiser, it's mostly there already, just settle on 1 secondary caliber (either the 125mm or the 100mm) and put the 250 tons used for training accomodations into extra armor plate and you're done.


On the sub-chaser:

Quoted

Caution: Poor stability - excessive risk of capsizing

A message that would be of some concern to me. Also, the top speed is a bit low, while it's sufficient to pursue submerged submarines, it means the pursuer is slower than most subs on the surface.

Most subs I've seen so far are capable of around 15 knots so the top speed isn't too bad, the stability is an issue I'd be worried about though.

The Indian I-15s, a likely adversary, can make over 18 knots on the surface.....

On the training ship, she's a handy size - 1 year to build, and has slack in the build. You're right, her sisters could be escorts, hadn't considered that in the design though. As for the mixed 100mm and 125mm- purely to make sure gunnery recruits have exposure to both the standard AA mounts.

Whoa, missed that stability warning.
However, the ship had lots of room to trim down, once under 48 it was ok. 38 gives 1.07.
She was built figuring on beating underwater speeds.

...
After fiddling trying high speeds, I found switching to diesel was advisable if I was trying for the higher speeds, and if I went to 21 for +3kts, then 25kts for 0.5 comp hull beckoned. Then the vessel doubled in size, I can't figure it out

SC-1, Netherlands Subchaser laid down 1935

Displacement:
249 t light; 257 t standard; 263 t normal; 268 t full load

Dimensions: Length overall / water x beam x draught
181.94 ft / 177.17 ft x 19.69 ft x 5.74 ft (normal load)
55.46 m / 54.00 m x 6.00 m x 1.75 m

Armament:
1 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1935 Model
Anti-aircraft gun in deck mount
on centreline forward
2 - 1.57" / 40.0 mm guns (1x2 guns), 1.95lbs / 0.88kg shells, 1935 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
4 - 0.91" / 23.0 mm guns (2x2 guns), 0.37lbs / 0.17kg shells, 1935 Model
Anti-aircraft guns in deck mounts
on side, all amidships
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1935 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 19 lbs / 8 kg
Shells per gun, main battery: 200

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.39" / 10 mm - -
2nd: 0.31" / 8 mm - -
3rd: 0.31" / 8 mm - -
4th: 0.31" / 8 mm - -

- Conning tower: 0.39" / 10 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 1 shaft, 2,688 shp / 2,006 Kw = 21.00 kts
Range 1,600nm at 8.00 kts
Bunker at max displacement = 12 tons

Complement:
32 - 42

Cost:
£0.109 million / $0.435 million

Distribution of weights at normal displacement:
Armament: 2 tons, 0.9 %
Armour: 1 tons, 0.4 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 1 tons, 0.3 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.1 %
Machinery: 76 tons, 29.0 %
Hull, fittings & equipment: 122 tons, 46.4 %
Fuel, ammunition & stores: 14 tons, 5.4 %
Miscellaneous weights: 47 tons, 17.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
251 lbs / 114 Kg = 19.5 x 3.0 " / 75 mm shells or 0.3 torpedoes
Stability (Unstable if below 1.00): 1.06
Metacentric height 0.5 ft / 0.1 m
Roll period: 11.8 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0.09
Seaboat quality (Average = 1.00): 1.05

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.460
Length to Beam Ratio: 9.00 : 1
'Natural speed' for length: 13.31 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 14.70 ft / 4.48 m
- Forecastle (15 %): 11.02 ft / 3.36 m (7.35 ft / 2.24 m aft of break)
- Mid (50 %): 7.35 ft / 2.24 m
- Quarterdeck (15 %): 7.35 ft / 2.24 m
- Stern: 7.35 ft / 2.24 m
- Average freeboard: 8.12 ft / 2.48 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 120.8 %
- Above water (accommodation/working, high = better): 93.7 %
Waterplane Area: 2,141 Square feet or 199 Square metres
Displacement factor (Displacement / loading): 120 %
Structure weight / hull surface area: 30 lbs/sq ft or 148 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.99
- Longitudinal: 3.10
- Overall: 1.11
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate

An attempt at a more worthy coastal protection vessel.
Equipped with hydrophones (10t) and depthcharges or mines (32t) there is little excess room (5t).

The ship is overbuilt, and not overly fast, but is perfectly capable of bird-dogging a submarine.
The 55m design means 2 should be buildable in a 120m slip, with 10m between

Here's an alternative that Germany expects to begin laying down in 1935. She's a touch heavier, though shorter, and has longer legs.

PB-1, German Patrol Boat laid down 1934

Displacement:
275 t light; 287 t standard; 305 t normal; 320 t full load

Dimensions: Length overall / water x beam x draught
164.04 ft / 164.04 ft x 18.04 ft x 6.56 ft (normal load)
50.00 m / 50.00 m x 5.50 m x 2.00 m

Armament:
2 - 3.46" / 88.0 mm guns in single mounts, 20.79lbs / 9.43kg shells, 1934 Model
Dual purpose guns in deck mounts
on centreline ends, evenly spread, 1 raised mount
2 - 1.46" / 37.0 mm guns (1x2 guns), 1.55lbs / 0.70kg shells, 1929 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
8 - 0.79" / 20.0 mm guns in single mounts, 0.24lbs / 0.11kg shells, 1928 Model
Machine guns in deck mounts
on side, evenly spread, 4 raised mounts
Weight of broadside 47 lbs / 21 kg
Shells per gun, main battery: 180

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.79" / 20 mm - -
2nd: 0.79" / 20 mm - -
3rd: 0.39" / 10 mm - -

- Conning tower: 1.97" / 50 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 3,631 shp / 2,709 Kw = 22.50 kts
Range 2,000nm at 12.00 kts
Bunker at max displacement = 34 tons

Complement:
36 - 47

Cost:
£0.143 million / $0.572 million

Distribution of weights at normal displacement:
Armament: 6 tons, 1.9 %
Armour: 6 tons, 1.8 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 4 tons, 1.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 2 tons, 0.6 %
Machinery: 104 tons, 34.2 %
Hull, fittings & equipment: 134 tons, 44.1 %
Fuel, ammunition & stores: 30 tons, 9.8 %
Miscellaneous weights: 25 tons, 8.2 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
214 lbs / 97 Kg = 10.3 x 3.5 " / 88 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.05
Metacentric height 0.4 ft / 0.1 m
Roll period: 11.6 seconds
Steadiness - As gun platform (Average = 50 %): 51 %
- Recoil effect (Restricted arc if above 1.00): 0.30
Seaboat quality (Average = 1.00): 1.22

Hull form characteristics:
Hull has raised forecastle
and transom stern
Block coefficient: 0.550
Length to Beam Ratio: 9.09 : 1
'Natural speed' for length: 14.64 kts
Power going to wave formation at top speed: 71 %
Trim (Max stability = 0, Max steadiness = 100): 42
Bow angle (Positive = bow angles forward): 0.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 16.40 ft / 5.00 m
- Forecastle (40 %): 14.76 ft / 4.50 m (7.38 ft / 2.25 m aft of break)
- Mid (50 %): 7.38 ft / 2.25 m
- Quarterdeck (15 %): 7.38 ft / 2.25 m
- Stern: 7.38 ft / 2.25 m
- Average freeboard: 10.60 ft / 3.23 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 134.8 %
- Above water (accommodation/working, high = better): 84.0 %
Waterplane Area: 2,151 Square feet or 200 Square metres
Displacement factor (Displacement / loading): 107 %
Structure weight / hull surface area: 26 lbs/sq ft or 125 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.80
- Longitudinal: 8.74
- Overall: 1.01
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is cramped
Good seaboat, rides out heavy weather easily

15 tons for hydrophones and sonar.

10 tons for depth charges and rails.

Hmm I like the German version a bit better than mine.
This is the 25knot version

SC-1, Netherlands Subchaser laid down 1935

Displacement:
283 t light; 295 t standard; 319 t normal; 338 t full load

Dimensions: Length overall / water x beam x draught
182.79 ft / 177.17 ft x 19.69 ft x 6.89 ft (normal load)
55.72 m / 54.00 m x 6.00 m x 2.10 m

Armament:
1 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1935 Model
Anti-aircraft gun in deck mount
on centreline forward
4 - 1.57" / 40.0 mm guns (1x4 guns), 1.95lbs / 0.88kg shells, 1935 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
4 - 0.91" / 23.0 mm guns (2x2 guns), 0.37lbs / 0.17kg shells, 1935 Model
Anti-aircraft guns in deck mounts
on side, all amidships
4 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1935 Model
Machine guns in deck mounts
on side, evenly spread
Weight of broadside 22 lbs / 10 kg
Shells per gun, main battery: 300

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.39" / 10 mm - -
2nd: 0.31" / 8 mm - -
3rd: 0.31" / 8 mm - -
4th: 0.31" / 8 mm - -

- Conning tower: 0.39" / 10 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 1 shaft, 6,421 shp / 4,790 Kw = 25.00 kts
Range 2,400nm at 12.00 kts
Bunker at max displacement = 43 tons

Complement:
37 - 49

Cost:
£0.162 million / $0.647 million

Distribution of weights at normal displacement:
Armament: 3 tons, 0.9 %
Armour: 1 tons, 0.4 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 1 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.1 %
Machinery: 139 tons, 43.7 %
Hull, fittings & equipment: 95 tons, 29.9 %
Fuel, ammunition & stores: 35 tons, 11.1 %
Miscellaneous weights: 45 tons, 14.1 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
102 lbs / 46 Kg = 7.9 x 3.0 " / 75 mm shells or 0.2 torpedoes
Stability (Unstable if below 1.00): 1.02
Metacentric height 0.5 ft / 0.1 m
Roll period: 12.3 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.16
Seaboat quality (Average = 1.00): 1.08

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.464
Length to Beam Ratio: 9.00 : 1
'Natural speed' for length: 13.31 kts
Power going to wave formation at top speed: 72 %
Trim (Max stability = 0, Max steadiness = 100): 65
Bow angle (Positive = bow angles forward): 18.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 17.32 ft / 5.28 m
- Forecastle (15 %): 17.32 ft / 5.28 m (9.32 ft / 2.84 m aft of break)
- Mid (50 %): 9.32 ft / 2.84 m
- Quarterdeck (15 %): 9.32 ft / 2.84 m
- Stern: 9.32 ft / 2.84 m
- Average freeboard: 10.52 ft / 3.21 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 164.2 %
- Above water (accommodation/working, high = better): 103.1 %
Waterplane Area: 2,150 Square feet or 200 Square metres
Displacement factor (Displacement / loading): 73 %
Structure weight / hull surface area: 18 lbs/sq ft or 88 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.49
- Longitudinal: 4.50
- Overall: 0.61
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform

An attempt at a more worthy coastal protection vessel.
Equipped with hydrophones (10t) and depthcharges or mines (30t) there is little excess room (5t).

The ship is overbuilt, but is perfectly capable of bird-dogging a submarine.
The 55m design means 2 should be buildable in a 120m slip, with 10m between.

Quoted

Originally posted by Hrolf Hakonson
The Indian I-15s, a likely adversary, can make over 18 knots on the surface.....

You know I didn't even think of looking at the Indian subs, though looking at the American SC-497 class 22 knots would seem respectable, which some of the latest versions in this post have now.

Submarine Chasers are poor ships, only suited to coastal work. You'd be better off using a design like the HDML or the Italian VAS. Essentially a MTB modified to take lower powered diesel engines and more room for depth charges. Small depth charges of around 50kg which are ample for coastal work. Of course, since they're only useful for coastal work the sonar set can be disposed of as its more or less useless in the clutter. The hydrophones will have to suffice. The sumbarine can't maneuver much whilst underwater or go fast. It'll still be lucky if you can sink it though. A better thing to do would be to use an aircraft to spot the submarine in the shallower water.

...of course there is always mines.....*Glares at Russia*

Quoted

Originally posted by Red Admiral
Submarine Chasers are poor ships, only suited to coastal work.

What I wanted was something in the 100-200 ton range, buildable 2 per type 0 slip, for employment in the Malay Achipelago and it's thousand islands.

The ships need to be simpler and lower maintenance - which is why the first design had compound engines, then diesels. Likewise my versions lack sonar (in part because that is relatively new to the Netherlands)

Three primary roles would be asked- generic coastal patrols, antisubmarine work, and if opposing forces go with PTB craft, escort work.

The first version was the right size and type, but the last works decently. Alternatives?

In other news, I had the notion that a triple 6" might be a bit much on the training cruiser's 13m beam- I can swap to 3x2 easily. Also, I don't have a transom, and it does help bolster hull strength, but I am unsure if it's reasonable on a mid-speed vessel.

Triples on 13m might be a little tight, agreed.

A transom on that vessel is probably not necessary or desirable: it will increase top end speed (at the same horsepower), but it will increase your fuel burn in most training operations and thus your costs.

Quoted

Alternatives?

Reciprocating engine, coal/wood burning boiler. Shallow draught. No 75mm gun. Just 2-4 40mm guns in singles and some 23mm AA. Hydrophones set. A cut down quarterdeck with depth charges on and a small boat.

Well, the first one I posted had reciprocating engines.
Considering the Malay Archipelago produces considerable quantities of oil, and lesser amounts of coal, I think oil burning is wiser than coal or wood.

Draught has ranged from 1.7-2.1m, already fairly shallow.

Freeboard is less than 3m already, but could be cut further on the stern.

Armament is more than you suggest, but certainly not out of line, and useful for the escort role should that need arise.

However, the sticking point was the speed. The original 13.5kts was deemed insufficient. Obtaining 21 - 25 knots yielded a 250-300 ton vessel.

A couple of 40mm guns is probably insufficient for dealing with a surfaced sub anyway, they won't penetrate the subs pressure hull and encourage the sub to try to fight it out on the surface. And, against only a couple of 40mms, the sub has a shot at winning..

I gave the subchaser a fresh try.

I again had to abandon the compound engines, and not being seduced by the transom led to some higher tonnage.

Speed was pegged at 25kts, keeping seakeeping acceptable was taking a vessel in the 48m+ range, so I went for 55m. Comes in at 190t light. Builds in 4.2 months, 2 to a Type 1 dock.


Misc: Figuring 10 tons for hydrophones, and 15 for K-guns and depth charges set a minimum of 25t. When the vessel was near done, it was obvious that the opportunity cost of an additional 10 tons was minimal, and can be a mine rail and provisions for minelaying.

Guns : Was going to use the new 45mm ATG, or Belgium's fortress 60mm ATG , but the opportunity cost of standardizing with the fleet's 75mm was...nothing.

A raised 23mm twin mount in the rear gives a clear firing arc over the DC's and other items aft.

The 13.2mms are for security and AA, with the forward 13.2mm allowing a visual detection and detonation of mines.

SC-6, Netherlands Subchaser laid down 1935

Displacement:
194 t light; 200 t standard; 204 t normal; 207 t full load

Dimensions: Length overall / water x beam x draught
186.73 ft / 180.45 ft x 16.08 ft x 4.92 ft (normal load)
56.91 m / 55.00 m x 4.90 m x 1.50 m

Armament:
1 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1928 Model
Anti-aircraft gun in deck mount
on centreline forward
2 - 0.91" / 23.0 mm guns (1x2 guns), 0.37lbs / 0.17kg shells, 1934 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
2 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1928 Model
Machine guns in deck mounts
on centreline ends, evenly spread
2 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1928 Model
Breech loading guns in deck mounts
on side, all amidships
Weight of broadside 14 lbs / 6 kg
Shells per gun, main battery: 200

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.39" / 10 mm - -
2nd: 0.31" / 8 mm - -
3rd: 0.31" / 8 mm - -

- Conning tower: 0.39" / 10 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 1 shaft, 4,694 shp / 3,502 Kw = 25.00 kts
Range 1,200nm at 8.00 kts
Bunker at max displacement = 8 tons

Complement:
26 - 35

Cost:
£0.107 million / $0.426 million

Distribution of weights at normal displacement:
Armament: 2 tons, 0.9 %
Armour: 1 tons, 0.3 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 0 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.1 %
Machinery: 91 tons, 44.4 %
Hull, fittings & equipment: 66 tons, 32.2 %
Fuel, ammunition & stores: 10 tons, 5.0 %
Miscellaneous weights: 35 tons, 17.2 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
65 lbs / 30 Kg = 5.1 x 3.0 " / 75 mm shells or 0.1 torpedoes
Stability (Unstable if below 1.00): 1.09
Metacentric height 0.4 ft / 0.1 m
Roll period: 11.0 seconds
Steadiness - As gun platform (Average = 50 %): 53 %
- Recoil effect (Restricted arc if above 1.00): 0.13
Seaboat quality (Average = 1.00): 1.06

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.500
Length to Beam Ratio: 11.22 : 1
'Natural speed' for length: 13.43 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 23.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 14.80 ft / 4.51 m
- Forecastle (20 %): 14.76 ft / 4.50 m (10.43 ft / 3.18 m aft of break)
- Mid (50 %): 6.43 ft / 1.96 m
- Quarterdeck (15 %): 6.43 ft / 1.96 m
- Stern: 6.43 ft / 1.96 m
- Average freeboard: 8.70 ft / 2.65 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 168.9 %
- Above water (accommodation/working, high = better): 100.1 %
Waterplane Area: 1,858 Square feet or 173 Square metres
Displacement factor (Displacement / loading): 64 %
Structure weight / hull surface area: 15 lbs/sq ft or 73 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.50
- Longitudinal: 3.01
- Overall: 0.60
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate

I'd be concerned about the short endurance: if it can only cruise for 1200 miles at 8 knots, how far can it go at full speed?

Quoted

Originally posted by Hrolf Hakonson
I'd be concerned about the short endurance: if it can only crise for 1200 miles at 8 knots, how far can it go at full speed?

Ummmmm At full bunkerage of 8 tons, it can go 55nm at 25kts.
Doesn't seem like much does it?

Worse, it's about 1,300nm from Banda Aceh to Ambon, and about 3,200nm across the archipelago.

So I tossed that spare 10t miscellaneous weight, and now it can make a whopping 170nm at 25kts...which means it can chase for at least a couple hours before heading for home.

====================================
SC-6, Netherlands Subchaser laid down 1935

Displacement:
187 t light; 193 t standard; 204 t normal; 213 t full load

Dimensions: Length overall / water x beam x draught
186.73 ft / 180.45 ft x 16.08 ft x 4.92 ft (normal load)
56.91 m / 55.00 m x 4.90 m x 1.50 m

Armament:
1 - 2.95" / 75.0 mm guns in single mounts, 12.87lbs / 5.84kg shells, 1934 Model
Anti-aircraft gun in deck mount
on centreline forward
2 - 0.91" / 23.0 mm guns (1x2 guns), 0.37lbs / 0.17kg shells, 1934 Model
Anti-aircraft guns in deck mount
on centreline aft, all raised guns - superfiring
2 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1928 Model
Machine guns in deck mounts
on centreline ends, evenly spread
2 - 0.52" / 13.2 mm guns in single mounts, 0.07lbs / 0.03kg shells, 1928 Model
Breech loading guns in deck mounts
on side, all amidships
Weight of broadside 14 lbs / 6 kg
Shells per gun, main battery: 200

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.39" / 10 mm - -
2nd: 0.31" / 8 mm - -
3rd: 0.31" / 8 mm - -

- Conning tower: 0.39" / 10 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 1 shaft, 4,694 shp / 3,502 Kw = 25.00 kts
Range 3,500nm at 8.00 kts
Bunker at max displacement = 19 tons

Complement:
26 - 35

Cost:
£0.107 million / $0.429 million

Distribution of weights at normal displacement:
Armament: 2 tons, 0.9 %
Armour: 1 tons, 0.3 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 0 tons, 0.2 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 0 tons, 0.1 %
Machinery: 93 tons, 45.7 %
Hull, fittings & equipment: 67 tons, 32.7 %
Fuel, ammunition & stores: 17 tons, 8.1 %
Miscellaneous weights: 25 tons, 12.3 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
69 lbs / 31 Kg = 5.3 x 3.0 " / 75 mm shells or 0.1 torpedoes
Stability (Unstable if below 1.00): 1.15
Metacentric height 0.4 ft / 0.1 m
Roll period: 10.5 seconds
Steadiness - As gun platform (Average = 50 %): 54 %
- Recoil effect (Restricted arc if above 1.00): 0.12
Seaboat quality (Average = 1.00): 1.07

Hull form characteristics:
Hull has raised forecastle
Block coefficient: 0.500
Length to Beam Ratio: 11.22 : 1
'Natural speed' for length: 13.43 kts
Power going to wave formation at top speed: 69 %
Trim (Max stability = 0, Max steadiness = 100): 50
Bow angle (Positive = bow angles forward): 23.00 degrees
Stern overhang: 0.00 ft / 0.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 14.80 ft / 4.51 m
- Forecastle (20 %): 14.76 ft / 4.50 m (10.43 ft / 3.18 m aft of break)
- Mid (50 %): 6.43 ft / 1.96 m
- Quarterdeck (15 %): 6.43 ft / 1.96 m
- Stern: 6.43 ft / 1.96 m
- Average freeboard: 8.70 ft / 2.65 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 167.8 %
- Above water (accommodation/working, high = better): 100.1 %
Waterplane Area: 1,858 Square feet or 173 Square metres
Displacement factor (Displacement / loading): 67 %
Structure weight / hull surface area: 15 lbs/sq ft or 74 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.51
- Longitudinal: 3.06
- Overall: 0.61
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate

8 tons fuels allows 55nm at 25kts.
19 tons fuel allows 170nm at 25knts

10t for hydrophones
15t for DC/Mines and mine rail.